{"id":38407,"date":"2025-05-06T00:01:39","date_gmt":"2025-05-06T04:01:39","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=38407"},"modified":"2025-05-05T10:06:34","modified_gmt":"2025-05-05T14:06:34","slug":"study-finds-aquatic-ecosystem-collapse-with-neonicotinoid-exposure-threatening-biodiversity","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2025\/05\/study-finds-aquatic-ecosystem-collapse-with-neonicotinoid-exposure-threatening-biodiversity\/","title":{"rendered":"Study Finds Aquatic Ecosystem Collapse with Neonicotinoid Exposure, Threatening Biodiversity"},"content":{"rendered":"

(Beyond Pesticides<\/em>, May 6, 2025) A study in Ecology Letters<\/em><\/a> finds \u201csevere degradation of ecosystem functioning in the form of loss of organic matter consumption and dramatic shifts in primary productivity,\u201d the researchers state, after performing an experiment with \u201c36 naturally established freshwater ecosystems exposed to increasing field-realistic concentrations of the neonicotinoid thiacloprid<\/a>.\u201d Aquatic communities<\/a> contribute to overall biodiversity<\/a> and are crucial in maintaining healthy ecosystems; without them, the entire food web<\/a> and vital ecosystem services<\/a>, such as nutrient cycling, water filtration, and climate regulation, are threatened.<\/p>\n

As the authors reference, there is a current unprecedented decline in biodiversity<\/a> that can be attributed to anthropogenic impacts. A multitude of studies connect pesticides, and more specifically neonicotinoid insecticides<\/a>, to impacts on aquatic ecosystems. (See studies here<\/a> and here<\/a>.) \u201cSince the community of organisms locally present is responsible for the functioning<\/a> of the local ecosystems,\u201d the researchers begin, \u201cthis begs the question: do neonicotinoid-induced shifts in community composition result in a degradation of ecosystem functioning?\u201d<\/p>\n

Previous research finds that neonicotinoids<\/a> can \u201cimpede several freshwater ecosystem processes such as organic matter (\u2018OM\u2019) decomposition, primary production or biomass transfer to neighbouring ecosystems,\u201d the authors say. (See studies here<\/a>, here<\/a>, and here<\/a>.) They continue: \u201cHowever, knowledge is lacking regarding to what extent neonicotinoid concentrations in surface waters actually affect natural freshwater biodiversity and how the functional coherence of the community is affected. To explore this gap, we analysed naturally assembled freshwater communities that were exposed to an environmentally realistic neonicotinoid concentration range.\u201d<\/p>\n

Through a two-tiered network-based approach, the researchers compare aquatic community structures and determine how neonicotinoid-induced stress disrupts ecosystem processes. As a result, they report, \u201cWe experimentally show that co-occurrence network approaches can identify the effects of a neonicotinoid at very low concentrations and that co-occurrence network disruption coincides with losses in ecosystem functioning.\u201d<\/p>\n

Assessing species co-occurrence, the pattern of two or more species within the same habitat, and changes to species with the introduction of an environmental stressor provides information on community structure and ecological variables that could cascade to further impacts. This experiment, conducted at an outdoor research facility at Leiden University in the Netherlands called the Living Lab, includes a setup of 36 experimental freshwater ditch ecosystems with a \u2018mesocosm\u2019 design to ensure similar habitat structure and conditions.<\/p>\n

As the authors describe: \u201cOur setup also allowed natural colonisation: We did not control how and which ecological invertebrate communities developed. This provided a controlled outdoor experimental design to study the effects of the neonicotinoid on naturally-formed communities and their environment.\u201d They allowed species to populate the ditches for five months before closing them off to the adjoining lake, sampling the macroinvertebrates for diversity, and then proceeding with two spikes, two weeks apart, of neonicotinoid exposure in the test groups.<\/p>\n

The environmentally relevant concentrations of thiacloprid<\/a> include 0, 0.1, 1, and 10\u2009\u03bcg\/L. Before exposure, the researchers confirmed the ditches did not have any significant differences in species abundance or other biotic or abiotic conditions (pH, temperature, etc.). After one month, the macroinvertebrates were sampled and analyzed again to assess impacts on the aquatic communities.<\/p>\n

The study considers multiple variables:<\/p>\n